In contrast to conventional analogue broadcasts, with terrestrial digital broadcasts, a sharp image can be obtained even if the incoming electromagnetic waves are received with more than a fixed level, since they constitute digital signals. An antenna for receiving terrestrial digital broadcasts therefore does not necessarily need to be of high gain. It may therefore be expected that this will make it possible to design antennas that are of smaller size and of a shape that is more easily handled than that of conventional antennas. As conventional UHF television antennas that are capable of operating in the UHF band, antennas are known whose principles of operation are based on Yagi/Uda antennas and in which a transmission element and reflector are arranged. In such antennas, the separation between the transmission element and reflector is usually about λ/4, where λ is the wavelength of the central frequency of the operating waveband. A known example of such an antenna is a skeleton slot array antenna (see non-patent reference 1).
Non-patent reference 1: Denshi Tsushin Gakkai Gijutsu Kenkyu Hokoku (Technical Research Reports of the Japanese Electronic Communication Association Vol. 87 No. 3A. P 87-5 Hiroyuki Nii and three others: Skeleton Slot Array Antenna for UHF-TV Reception (Apr. 16, 1987).